OT2_rhuub_2: The formation and evolution of proto-clusters

Understanding how massive black holes, galaxies and clusters of galaxies jointly emerged from inhomogeneities in the primeval Universe is one of the most compelling objectives of modern observational astrophysics. Here we propose to use SPIRE's excellent sensitivity and survey speed to obtain for the first time a significant sample of proto-clusters over the key redshift range 2 < z < 4. This would be done through imaging of fields centered at AGN selected to harbour the most massive black hole. The resulting data set will allow us to address key questions, including: (i) Are the most massive black holes at z > 2 located in the largest and most massive proto-clusters? (ii) What are the masses, sizes, total star formation rates and velocity dispersions of the protoclusters? (iii) What are the masses, ages and star formation rates of the individual proto-cluster galaxies? Do we see a spatial segregation of galaxies with different masses or star formation rates? (iv) Do the properties of the proto-clusters and their galaxies evolve with redshift? (v) Are the galaxies in these proto-clusters older, larger and more massive then field galaxies?